In
this section, I will cover the major ways plants and animals adapt to the water
and temperature stresses they experience around Tucson, AZ. When we think of
deserts, and Tucson's desert is no exception, we usually think of blistering
heat and death by dehydration (you know the saying, "At least it's a dry
heat"). You can go to the climate
section to see just how hot and dry it is around Tucson. Yet, plants and animals
still thrive in our desert. How do they do it? Below you will find a general
outline.

There
are three basic methods plants and animals use to live in the desert.

Expire
When the going gets tough, die...
but leave behind tough seeds/eggs. This is what our annual wildflowers
do, like this bahia and its seeds.

Evade
When the going gets tough, leave...
go north or south, go up or down a mt., change activity from day to night
or from above ground to below. Here is a kangaroo
rat asleep in its burrow during the hot day (see torpor).

Endure
When the going gets tough, take it...
but you better have good desert adaptations like these plants.

Strategies
to ENDURE the harsh desert conditions are many, but can be organized as follows:

Ways
to Endure Lack of Water:

Store
Water
Water can be stored by animals in fatty deposits in their tails and other
tissues (e.g., in the gila monster's
tail). Water can be stored in the roots, stems, and/or leaves of plants
(plants that do this are called succulents).

Conserve
WaterMinimize loss of water out of the skin
(cutaneous loss), from urine and feces (excretory loss), and from "breathing"
(respiratory loss) through various means (e.g., see torpor).

Tolerate
Dehydration
Many of the desert plants (e.g., this prickly
pear cactus) and animals (e.g., desert toads) can tolerate great losses
of water out of their bodies without dying.

Ways
to Endure High Temperatures:

Reduce
Heat Input
This can be done by staying out of the sun, by shading (e.g., spines/fur),
by posture and orientation (e.g., orienting leaves vertically to minimize
surface area directly hit by sun), by insulation, by shiny surfaces that
reflect sun, etc.

Dissipate
Heat
If heat reduction wasn't enough, then it is time to get rid of body heat
by evaporation (costs water though), long appendages (legs, ears, etc.),
or small "bodies" (e.g., whole body,
leaves, etc.) that radiate heat.

Tolerate
Hyperthermia
Some plants and animals can survive body temperatures that would be dangerous
to humans (e.g., this antelope squirrel
tolerates body temperatures over 104 degrees F!).